1. Field
The following description relates to a device and method for increasing energy efficiency by clipping an input signal to meet both a peak to average power ratio (PAPR) and a bit error ratio (BER) within a target band.
2. Description of Related Art
Currently, an orthogonal frequency division modulation (OFDM) technology is used for high speed transmission of large amounts of data. When the OFDM scheme is used, a peak to average power ratio (PAPR) of an OFDM signal may reduce an efficiency of a high power amplifier (HPA) of a communication device. Such a communication device may include a fixed base station, a mobile base station, a micro base station such as a femto base station, a data transmitter such as a relay, a fixed terminal device, a mobile terminal device, a data receiver such as a relay, and the like.
Generally, a communication device may increase efficiency of a high power amplifier using discrete Fourier transform-spread-OFDM (DFT-S-OFDM) or single carrier-frequency division multiple access (SC-MMA). When the DFT-S-OFDM or SC-FDMA is used, the communication device may spread signals from a frequency domain through DFT.
However, although the efficiency of the large power amplifier may be increased by reducing the PAPR using SC-FDMA, a pilot overhead may be increased and a link performance may be reduced in higher dimensional modulation such as 16 quadrature amplitude modulation (QAM) or 64 QAM. Reduction in the link performance may create an inter symbol interference (ISI), consequently reducing power efficiency of the communication device.
Accordingly, there is a need for a technology for increasing power efficiency even when high dimensional modulation is applied.